Added a problem

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Mark 2023-10-06 14:12:42 -07:00
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@ -101,4 +101,26 @@
\end{itemize} \end{itemize}
\vfill
\pagebreak
\problem{}
Let $f$ be a function from a set $X$ to a set $Y$. We say $f$ is \textit{injective} if $f(x) = f(y) \implies x = y$. \par
We say $f$ is \textit{surjective} if for all $y \in Y$ there exists an $x \in X$ so that $f(x) = y$. \par
Let $A, B, C$ be sets, and let $f: A \to B$, $g: B \to C$ be functions. Let $h = g \circ f$.
\vspace{2mm}
\begin{itemize}
\item Show that if $h$ is injective, $f$ must be injective and $g$ may not be injective.
\item Show that if $h$ is surjective, $g$ must be surjective and $f$ may not be surjective.
\end{itemize}
\vfill
\pagebreak
\problem{}
\end{document} \end{document}